Two-way lock for telescoping stand



Feb. 2, 1960 D. J. BROWN TWO-WAY LOCK FOR TELESCOPING STAND Filed May 1,i957 Jzve %071- wZZZ/ZZ/QZ j United States Patent TWO-WAY LOCK FORTELESCOPING STAND Donald J. Brown, Melrose Park, Ill., assignor toBretford Manufacturing, Inc., Franklin Park, Ill., a corporation ofIllinois Application May 1, 1957, Serial No. 656,290

9 Claims. (Cl. 287-58) This invention relates to portable stands and,more particularly, to a two-way locking mechanism for a telescopingpicture screen stand.

Most portable picture screen stands on the market utilize a pair oftelescoping rod members which are longitudinally adjustable forsupporting the picture screen in open'position. Adjustment of the rodmembers has commonly been provided by a clamping member which ispositioned on one rod member and has a portion embracing the other rodmember. The embracing portion is normally tipped by a spring member soas to frictionally engage the other rod member. Such clamping memberswere capable of maintaining the rod members against relative movement inone direction only.

When displaying a picture screen in a camera shop, it is desirable thatthe telescoping rods be held against relative movement in bothdirections so that the head of one of the telescoping rods will remainin firm engagement with the end of a screen casing, until released. Thepresent invention provides a particularly unique and inexpensivestructure for accomplishing this two-Way locking.

The primary object of the present invention is to provide a new andimproved locking mechanism for a telescoping stand. I

Another object is to provide a locking mechanism which is adapted tohold a pair of telescoping members against longitudinal movement ineither of two opposite directions.

A further object is to provide a locking mechanism having a singleclamping member mounted for slight longitudinal movement on a tubularrod member so as to utilize two points of pivot for biasing the clampingmember into gripping engagement with a second rod member, the clampingmember pivoting from one point to maintain gripping engagement when thesecond rod member is urged in one direction, and having a second pointof pivot to maintain gripping engagement when the rod member is urged inan opposite direction.

The invention is illustrated in a preferred embodiment in theaccompanying drawings, in which:

Fig. 1 is a fragmentary side elevational view of the locking mechanismshowing the spring and screen casing in dotted outline;

Fig. '2, a sectional view taken as indicated on line 2-2 of Fig. 1 andshowing a projection of the bail support engaging an end cap of thescreen casing;

Fig. 3, a top plan view; and

Fig. 4, a sectional'view taken as indicated on line 4-4 ofFig. 2.

In the embodiment illustrated, and as best seen in Fig. 2, an uprightstandard, generally designated 10, is formed from a pair of elongatedrod members 11 and 12 which are conventionally supported in uprightposition by a conventional base member, not shown. The rod member -11,preferably made from metal, is tubular and of a size to telescopinglyreceive the extensible rod member 12. The lower end of the rod member 12may be centered and guided within the tubular rod member 11 in a man-2,923,564 Patented Feb. 2, 1960 14. The cap member 13 is apertured, asat 15, to make a close sliding fit with the extensible rod member 12.

A conventional bail support 16 may be secured to the upper free end ofthe rod member 12. The bail support 16 is notched as at 17 for receivingthe hail of a picture screen, not shown, and it has a projecting nose 18adapted to fit into a depression 20 of an end cap 21. The engagement ofthe bail support 16 and the end cap 21 holds the screen casing 22 insecure alinement adjacent the standard 10 when it is desired to place ascreen stand on display or in carrying position.

Means are provided for locking the rod member 12 in varying degrees ofextended position with respect to the tubular rod member 11. As hereinbest shown in Fig. 2, a clamping member, generally designated 23, andpreferably L-shaped in configuration, is provided with an actuatingfinger element 24 and a gripping portion 25. The gripping portion 25projects through a slot 26 in the lateral surface of the tubular member11 and extends shown in Fig. 2. By moving the gripping portion 25 to aposition perpendicular to the rod member 12, the rod member 12 is freeto be moved upwardly or downwardly within the tubular rod member 11 tothe desired degree of extension.

Spring means is preferably provided normally to bias and urge thegripping portion 25 into frictional engagement with the rod member 12.As herein shown, a resilient wire spring 30 may be bent into a generallyU-shaped configuration and inserted through the slot 26 so that springarms 31 and 32 bear in opposite directions upon the rod member 12 andthe finger element 24, respectively, causing the clamping member to bebiased into gripping engagement to hold the rod member 12 fromtelescoping into the tubular rod member 11. Downward forces upon the rodmember 12 tend to pivot the clamping member 23 about point 28 into evenfirmer gripping engagement.

To effect a two-way locking, the structure of the present invention isarranged to reverse the point of pivot of the clamping member 23 whenupward forces are exerted upon the rod member 12 so that the clampingmember is retained in gripping engagement. To this end a shoulder 33 ispreferably provided in thetubular rod member 12 opposite the slot 26 forengagingan end 35 of the clamping member 23. The shoulder 33 may bestruck inwardly from the tubular rod member 11, or the tubular rod maybe slotted to accommodate a projection from the end 35 of the clampingmember 23.

As herein shown, the shoulder 33 is provided by a machine screw 34secured to the tubular rod member 11;

When the rod member 12 is pulled upwardly, the slot 26 permits slightlongitudinal movement of the rod mem-, ber 12 together with the clampingmember 23. During clamping member 23 counterclockwise into even firmergripping engagement with the rod member 12. By providing a structureadapted to shift the pivoting of the clamping member 23 between oppositesides of the extensible rod member 12, gripping engagement of theclamping member is maintained against forces in opposite longitudinaldirections, and a two-way locking is effected. If the longitudinalmovement were not provided, upward forces on the rod member 12 wouldsimply overcome the force of the spring 26 and pivot the clamping member23 on the edge of the slot above the clamping member which woulddisengage the rod member 12.

It should be further noted that the shoulder 33 is positioned to permitmanual pivoting of the clamping member 23 from a gripping to anon-gripping position when the clamping member is resting at the lowerend of the slot 26. To extend, or to telescope, the rod member 12 it ismerely necessary to pivot the clamping member by the finger element 24,and move the rod member to the desired degree of extension.

Although not shown, it is conventional to pivot the screen casing 22 toa bracket on the tubular rod member 11. This permits the screen casingto be positioned parallel to the two rod members when it is desired todisplay the screen or to carry it. As can be seen in Fig. 2, thedistance which the projecting nose 18 fits into the depression 20 isslightly greater than the longitudinal movement provided by the slot 26and shoulder 33 so that the nose of the bail support will remain firmlyin engagement with the end cap 21 of the casing 22 until released by thefinger element 24.

The foregoing detailed description is given for clearness ofunderstanding only and no unnecessary limitations should be understoodtherefrom as some modifications will be obvious to those skilled in theart.

I claim:

1. An extensible rod assembly, comprising: a pair of elongated rodmembers, the first of said rod members being tubular and having an endfor telescopingly receiving the second rod member, said tubular rodmember having a slot in its lateral surface; a clamping member pivotedon an edge about said slot and having a transversely extending endprovided with a gripping portion for engaging the second rod member,said gripping portion being movable between a tilted gripping and anongripping position by pivoting the clamping member, said slot being ofa size to permit slight longitudinal movement of the clamping memberwhen in gripping engagement with the second rod member; a springnormally yieldingly pivoting said clamping member on the edge of saidslot to urge said gripping portion into said gripping position to holdsaid second rod member against movement in one direction; and a shoulderon the tubular rod member spaced laterally from the slot for engagingsaid end of the clamping member to limit said slight longitudinalmovement of the clamping member, the engagement of the shoulder and theend of the clamping member retaining said gripping portion in tiltedgripping position to hold said second rod member against movement in anopposite direction.

2. An extensible rod assembly as specified in claim 1, in which theshoulder projects inwardly of the tubular rod member and is positionedto engage the end of the clamping member during said slight longtudinalmove-.

ment.

3. An extensible rod assembly as specified in claim 1, in which thegripping portion of the clamping member is provided with an opening, andthe second rod is longitudinally slidable through said opening when thegripping portion is moved to non-gripping position, the spring normallypivoting the clamping member so that the gripping portion about saidopening engages and holds the second rod member.

4. An extensible rod assembly as specified in claim 1, in which theclamping member is provided with a finger element for manually pivotingthe gripping portion to its non-gripping position.

5. An extensible rod assembly as specified in claim 4, wherein thespring has two arms arranged in a U-shaped configuration, the springextending through the slot in the tubular rod member and having one armbearing outwardly against the finger element and the other arm bearingagainst the second rod member normally to pivot said clamping member andgripping portion into gripping position.

6. A telescoping stand adapted to be supported in an upright position,comprising: an elongated tubular rod member having a longitudinallyextending slot adjacent its upper end portion; a second rod membertelescoping- 1y received in said tubular rod member; a clamping memberprojecting through said slot and having a gripping portion forfrictionally engaging said second rod member, said clamping member beingmanually movable between a tilted gripping and a non-gripping position,the slot being of a size to permit slight longitudinal movement of theclamping member and the second rod member when in gripping engagement; acooperating spring normally biasing the clamping member into frictionalgripping engagement to hold said second rod member against movement inone direction, said spring holding the clamping member in grippingposition with the second rod member during said slight longitudinalmovement; and a shoulder on the tubular rod member for engaging said endof the clamping member to limit said slight longitudinal movement of theclamping member, the engagement of the shoulder and the end of theclamping member retaining said gripping portion in gripping position tohold said second rod member against movement in an opposite direction.

7. A telescoping stand adapted to be supported in an upright position,comprising: an elongated tubular rod member, having a longitudinallyextending slot and an oppositely disposed shoulder in its upper endportion; a second rod member slidingly received in said tubular rodmember, said second rod member being movable between telescoped positionand a plurality of extended positions; and a clamping member projectingthrough said slot inwardly of the tubular rod member and normally urgedinto frictional gripping engagement with said second rod member, saidclamping member being pivoted upon an edge of said slot for manualmovement between a tilted gripping and a non-gripping position, saidedge of the slot and said shoulder providing a pair of pivots for theclamping member whereby downward forces on said second rod member pivotsaid clamping member about said slot edge toward gripping position, andupward forces on said second rod member carry the clamping memberupwardly in said slot into engagement with said oppositely disposedshoulder to pivot said clamping member toward gripping position.

8. An extensible rod assembly adapted to be supported in an uprightposition, comprising: a pair of elongated rod members, the first of saidrod members being tubular and having an end for telescopingly receivingthe second rod member, said tubular rod member having a longitudinalslot in its lateral surface; a clamping member pivoted on an edge aboutsaid slot and having a transversely extending end provided with agripping portion for engaging the second rod member, said grippingportion being movable between a tilted gripping and a nongrippingposition by pivoting the clamping member, said slot being of a size topermit slight longitudinal movement of the clamping member upwardly whenin gripping engagement with the second rod member; a spring normallyyieldingly urging said gripping portion into said gripping position sothat downward forces on the second rod member tend to pivot the grippingportion about the edge of the slot toward gripping position; and ashoulder on the tubular rod member spaced laterally from the slot andpositioned upwardly from said edge of the slot on which the clampingmember is pivoted so that the gripping portion of the clamping membercan be manually pivoted to a non-gripping position, said shoulder beingpositioned for engagement with the transversely extending end of theclamping member so as to limit said slight longitudinal movement of theclamping member when the second rod member is pulled upwardly wherebythe clamping member is caused to bear against said shoulder and retainthe clamping member in gripping position to effect locking againstupward movement of said second rod member.

9. An extensible rod assembly adapted to be supported in an uprightposition, comprising: a pair of elongated rod members, the first of saidrod members being tubular and having an end for telescopingly receivingthe second rod member, said tubular rod member having a longitudinalslot in its lateral surface; a clamping member pivoted on an edge aboutsaid slot and having a transof the clamping member upwardly when ingripping fl gagement with the second rod member; a spring normallyyieldingly urging said gripping portion into said gripping position; anda shoulder on the tubular rod member spaced laterally from the slot andbeing positioned upwardly from said edge of the slot from which theclamping member is pivoted for engagement with the transverselyextending end of the clamping member, said edge of the slot and saidshoulder providing a pair of pivots for the clamping member wherebydownward forces on said second rod member pivot said clamping memberabout said slot edge toward gripping position, and upward forces of saidsecond rod member carry the clamping member upwardly in said slot intoengagement with said shoulder to pivot and urge said clamping membertoward gripping position.

References Cited in the file of this patent UNITED STATES PATENTS717,834 Fornander Jan. 6, 1903 836,303 Chistensen Nov. 20, 19062,595,647 Du Mais May 6, 1952

